Metallicity gradients in disks: Do galaxies form inside-out?

Show simple item record

dc.creator Pilkington, K.
dc.creator Few, C. G.
dc.creator Gibson, Brad K.
dc.creator Calura, F.
dc.creator Michel-Dansac, L.
dc.creator Thacker, Robert John, 1970-
dc.creator Molla, M.
dc.creator Matteucci, F.
dc.creator Rahimi, A.
dc.creator Kawata, D.
dc.date.accessioned 2018-04-16T15:17:58Z
dc.date.available 2018-04-16T15:17:58Z
dc.date.issued 2012-04
dc.identifier.issn 0004-6361
dc.identifier.uri http://library2.smu.ca/handle/01/27416
dc.description Publisher's Version/PDF
dc.description.abstract Aims. We examine radial and vertical metallicity gradients using a suite of disk galaxy hydrodynamical simulations, supplemented with two classic chemical evolution approaches. We determine the rate of change of gradient slope and reconcile the differences existing between extant models and observations within the canonical “inside-out” disk growth paradigm. Methods. A suite of 25 cosmological disks is used to examine the evolution of metallicity gradients; this consists of 19 galaxies selected from the RaDES (Ramses Disk Environment Study) sample, realised with the adaptive mesh refinement code RAMSES, including eight drawn from the “field” and six from “loose group” environments. Four disks are selected from the MUGS (McMaster Unbiased Galaxy Simulations) sample, generated with the smoothed particle hydrodynamics (SPH) code GASOLINE. Two chemical evolution models of inside-out disk growth were employed to contrast the temporal evolution of their radial gradients with those of the simulations. Results. We first show that generically flatter gradients are observed at redshift zero when comparing older stars with those forming today, consistent with expectations of kinematically hot simulations, but counter to that observed in the Milky Way. The vertical abundance gradients at ∼1–3 disk scalelengths are comparable to those observed in the thick disk of the Milky Way, but significantly shallower than those seen in the thin disk. Most importantly, we find that systematic differences exist between the predicted evolution of radial abundance gradients in the RaDES and chemical evolution models, compared with the MUGS sample; specifically, the MUGS simulations are systematically steeper at high-redshift, and present much more rapid evolution in their gradients. Conclusions. We find that the majority of the models predict radial gradients today which are consistent with those observed in late-type disks, but they evolve to this self-similarity in different fashions, despite each adhering to classical “inside-out” growth. We find that radial dependence of the efficiency with which stars form as a function of time drives the differences seen in the gradients; systematic differences in the sub-grid physics between the various codes are responsible for setting these gradients. Recent, albeit limited, data at redshift z ∼ 1.5 are consistent with the steeper gradients seen in our SPH sample, suggesting a modest revision of the classical chemical evolution models may be required.  en_CA
dc.language.iso en en_CA
dc.publisher EDP Sciences en_CA
dc.relation.uri https://dx.doi.org/10.1051/0004-6361/201117466
dc.rights Article is made available in accordance with the publisher’s policy and is subject to copyright law. Please refer to the publisher’s site. Any re-use of this article is to be in accordance with the publisher’s copyright policy. This posting is in no way granting any permission for re-use to the reader/user.
dc.subject.lcsh Cosmic abundances
dc.subject.lcsh Galaxies -- Evolution
dc.subject.lcsh Galaxies -- Formation
dc.title Metallicity gradients in disks: Do galaxies form inside-out? en_CA
dc.type Text en_CA
dcterms.bibliographicCitation Astronomy & Astrophysics 540, A56. (2012) en_CA


Files in this item


 

Copyright statement:

 
Article is made available in accordance with the publisher’s policy and is subject to copyright law. Please refer to the publisher’s site. Any re-use of this article is to be in accordance with the publisher’s copyright policy. This posting is in no way granting any permission for re-use to the reader/user.
 
Published Version: https://dx.doi.org/10.1051/0004-6361/201117466
 
 

This item appears in the following Collection(s)

Show simple item record